The resistive force in a fluid depends on which factors?

The resistive force experienced by an object moving through a fluid, commonly referred to as drag, is primarily influenced by its speed and the viscosity of the fluid. As the speed of the object increases, the resistive force typically increases as well because the object interacts more vigorously with the fluid molecules, resulting in greater friction between them.

Viscosity is a measure of a fluid's resistance to flow; a more viscous fluid will exert a higher resistive force on the moving object. Therefore, both the speed of the object and the thickness (or viscosity) of the liquid are critical factors in determining the magnitude of the drag force acting on it.

Other options may touch on related concepts but do not directly encompass the main factors that define resistive forces in fluids. For instance, while temperature and density might influence fluid properties, they are not the primary determinants of drag in motion. Mass and volume pertain more to the object's inertia rather than the direct interaction with the fluid. Shape and surface area are also important, particularly in the context of how they impact drag, but they are more directly related to specific configurations rather than defining the resistive force in terms of fluid dynamics.